[lldb] Add StringList::AppendString(const Twine&) (NFC)

[kastiglione]

Summary

Add a convenience for appending constructed string values.

[JDevlieghere]

Ship it

lldb/include/lldb/Utility/StringList.h

 //===-- StringList.h --------------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLDB_UTILITY_STRINGLIST_H
 #define LLDB_UTILITY_STRINGLIST_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
 
 #include <cstddef>
 #include <string>
 #include <vector>
 
 namespace lldb_private {
 class Log;
 class Stream;
public:
   void AppendString(std::string &&s);
 
   void AppendString(const char *str);
 
   void AppendString(const char *str, size_t str_len);
 
   void AppendString(llvm::StringRef str);
 
+  void AppendString(const llvm::Twine &str);
+
   void AppendList(const char **strv, int strc);
 
   void AppendList(StringList strings);
 
   size_t GetSize() const;
 
   void SetSize(size_t n) { m_strings.resize(n); }
 

lldb/source/Utility/StringList.cpp

void StringList::AppendString(const char *str, size_t str_len) {
   if (str)
     m_strings.push_back(std::string(str, str_len));
 }
 
 void StringList::AppendString(llvm::StringRef str) {
   m_strings.push_back(str.str());
 }
 
+void StringList::AppendString(const llvm::Twine &str) {
+  m_strings.push_back(str.str());
+}
+
 void StringList::AppendList(const char **strv, int strc) {
   for (int i = 0; i < strc; ++i) {
     if (strv[i])
       m_strings.push_back(strv[i]);
   }
 }
 
 void StringList::AppendList(StringList strings) {